Re: starship-design: This and that.

[Steve VanDevender <stevev@efn.org>]

kyle writes:
 > > The problem is that if you go faster than light Einstein's equations
 > > start producing complex numbers (that is, numbers with both real and
 > > imaginary components) as results.  Nobody knows how to interpret the
 > > imaginary components in a physical context, nor has any evidence of
 > > physical phenomena with these quantities been seen.
 > 
 > Maybe because we haven't done it yet? 

If FTL is possible, then there's a good chance that it can happen as
part of some natural phenomenon, and that would produce pretty
noticeable effects.  Not observing FTL in the natural universe is a
pretty good indication that it can't be _too_ easy.  Nevertheless, any
FTL method will have to be reconciled with relativity and quantum
mechanics, both of which have been extensively tested by experiment and
for which there aren't any widely-acknowledged exceptions.

 > The loopholes may have their problems, but it is too early to dismiss
 > FTL travel. FTL communication CANNOT be dismissed. It has been done
 > already. I know you won't believe it, but most people don't believe
 > things that are hard to accept against relativity.

If FTL communication "CANNOT be dismissed", then you're implying it has
been experimentally demonstrated in a very obvious way.  When was that?
I apparently missed the news.

 > BTW: Have you heard of autodynamics? According to it FTL is easily
 > possible. And who's to say that relativity is the almighty God of
 > physics? Maybe its not. 

Is autodynamics experimentally demonstrated?  You're claiming it makes
predictions that relativity would not, so if it is to be accepted these
predictions have to be observable in reality.

Relativity is a widely accepted theory because it makes predictions that
have been matched with reality.  It displaced Newton's theories of
dynamics because it made predictions that Newton's theories did not, and
experiment matched Einstein's theory better than Newton's for domains
that weren't easily accessible to previous experimenters.  We may
certainly find relativity revised when experimenters have access to
domains in which relativity has not been extensively tested.  However,
note that Newton's theories are still taught because, at low velocities
and energies, they are accurate enough.  Similarly I expect whatever
might come after relativity to not completely abandon its strictures in
the domains for which it's been tested.

 > Remember Arthur C. Clarke's states of developing a theory:
 > 
 > 1: Its impossible, don't waste my time.
 > 2: Its possible but impractical
 > 3: I agreed with you all along

In order for that progression to work, you have to have a working
theory, that is, one that can be tested against reality and which passes
its tests.  You can't do that with just any theory; most theories
proposed by scientists are wrong, and fail their tests, and are never
heard of again.  The theories that survive are the ones that pass their
tests over and over and over again.  We have theories like that in
relativity and quantum mechanics.  They may not be perfect, but they're
the best we've got, and you can't displace them without coming up with
something that doesn't contradict what we already know.